The main change in this update is a new steamworks based server browser. It should find games faster and more reliably.
Also added a few items:
-Magnetic ammo for bombs/mines. It drifts towards nearby enemies.
-Safety ammo for most projectiles, which reduces self/friendly fire damage.
-Trident mod is now a barrel rather than an ammo type, allowing you to combine it with singularity warheads etc.